A phantom for use in an MRI or MRS system includes an array of subresolvable compartments that are each connected to receive fluid from one of a plurality of fluid reservoirs. The array of compartments is divided into sub-arrays which differ from each other by the mix of compartments in each sub-array receiving fluids from the different reservoirs. Studies can be performed with the phantom by filling the compartments with selected fluids from the reservoirs, disconnecting the reservoirs and placing the phantom in the system bore. The phantom can be reused in other studies by replacing the fluids with different fluids.